1. Field of the Invention
The present invention relates to a back-pressure sealing system for a revolving compressor, particularly to a back-pressure sealing system of simple structure, high durability and stability, allowing for high pressures.
2. Description of Related Art
Air conditioners and refrigerators use compressors as central devices, which are expected to exchange heat effectively, with little noise and for a long lifetime. Good quality of compressors contributes to energy-saving. Compressors are expensive devices, to replace or repair them results in material and work costs, and to exchange the refrigerant is costly and harms the environment. Therefore improving compressors is an important task.
FIG. 2 is a schematic illustration of a conventional rubber back-pressure sealing system in a revolving compressor. A revolving compressor basically has a motor 5, driving an eccentric shaft 4, which in turn drives a rotor 6. An Oldham ring 7 allows the rotor 6 to revolve around the axis of rotation of the motor 5, engaging with a stator 8, and at the same time prevents the rotor 6 from rotating around its own axis. The movement of the rotor 6 causes a liquid agent to be let into the space between the rotor 6 and the stator 8, compressed there and let out from there. For good operation, the stator 8 has to be sealed effectively on the axis of the revolving movement of the rotor 6. Any leakage from the outlet chamber would let the rotor 6 revolve non-uniformly and thus cause noise and wear.
Taiwan patent no. 107089 and U.S. Pat. No. 5474433 disclose a sealing system. As shown in FIG. 2, a conventional back-pressure sealing system is characterized by the following: (1) A rubber sealing ring (O-ring) 1A of appropriate size is laid into a peripheral groove 821 on the stator 8, sealing the stator 8 against an inner wall 95 of a separating part 9. Thereby a high-pressure zone 14 is separated from a low-pressure zone 12. (2) Rubber sealing rings 1B of appropriate sizes are laid into grooves in accommodation chambers 93 of a connecting system to the high-pressure zone, for preventing leakage through the separating part 9.
When the sealing system described above is installed under no high pressure and temperature, the sealing effect is good. However, the location of the sealing system is normally exposed to liquid of high pressure and temperature, and the structural elements there start to glide against each other along the revolving axis. After prolonged use the sealing rings swell and become soft. Vibrations of the structural elements next to the sealing ring cause wear and corrosion of the sealing ring, such that the liquid agent leaks through.